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Stratum corneum keratin structure, function, and formation: the cubic rod-packing and membrane templating model
Lars Norlén1, Ashraf Al-Amoudi
1Group of Applied Physics-Biomedical, Department of Physics, University of Geneva, Geneva, Switzerland. lars.norlen@physics.unige.ch
The Journal of Investigative Dermatology
|September 18, 2004
Summary
A new model proposes stratum corneum keratin filaments form via membrane templating and arrange in cubic rod packing. This explains keratin structure, function, and formation in mammalian skin.
Area of Science:
- Biophysics
- Cell Biology
- Dermatology
Background:
- Stratum corneum keratin structure and formation are not fully understood.
- Existing models do not fully explain keratin behavior in mammalian skin.
Purpose of the Study:
- To present a new integrated model for stratum corneum keratin structure, function, and formation.
- To explain keratin intermediate filament arrangement and assembly dynamics.
Main Methods:
- Development of a novel 'cubic rod-packing model' for keratin structure and function.
- Development of a 'membrane templating model' for keratin formation.
- Cryo-transmission electron microscopy (cryo-TEM) of native epidermis.
Main Results:
- The cubic rod-packing model explains cryo-electron density, X-ray diffraction, swelling, and mechanical properties.
- The membrane templating model explains keratin network formation, dynamics, and lipid association.
- Cryo-TEM reveals subfilametous keratin patterns in both viable and corneocytes, with ~8 nm filament diameter.
Conclusions:
- A unified model integrating cubic rod-packing and membrane templating accurately describes stratum corneum keratin.
- Membrane templating is proposed as the primary mechanism for keratin intermediate filament formation.
- The model provides a comprehensive framework for understanding keratin's role in skin structure and barrier function.